Method for improving recovery ratio of oil field by use of blasting type pre-crosslinking gel particles

Abstract

The invention provides a method for improving the recovery ratio of an oil field by use of blasting type pre-crosslinking gel particles, and particularly relates to a method for improving the recovery ratio of an old oil field with high water cut. The method adopts a kind of pre-crosslinking gel particles; the pre-crosslinking gel particles absorb water to expand and form a solution after staying for a certain time at the formation temperature and pH condition; and the method for improving the recovery ratio of an old oil field with high water cut comprises the following steps of: mixing the pre-crosslinking gel particles with water so that the pre-crosslinking gel particles absorb water to expand; injecting the pre-crosslinking gel particles underground so that the pre-crosslinking gel particles firstly block big pore channels and ultrahigh-permeability layers near the well in an oil pool, wherein after the pre-crosslinking gel particles experience the action of the oil pool temperature for a certain time, the gel particles automatically blast to form a polymer viscose solution which enters the deep of the oil pool to realize control on oil-water fluidity; and performing oil extraction. The method provided by the invention is suitable for improving the petroleum recovery ratio of the oil pool at the stage of high water cut.

Description

technical field [0001] The present invention relates to a method for increasing the recovery rate of an oilfield, especially an old oilfield with a high water content, in oil exploitation, and in particular to a method for improving the recovery rate of an oilfield by using a blasting pre-crosslinked gel particle with dual functions of profile control and polymer flooding method. Background technique [0002] With the continuous development of the oil field, the heterogeneity of the reservoir is becoming more and more serious. A large amount of injected water scours, the clay and cement in the oil layer expand and dissolve, the migration of particles, and the sand production become heavier, which further deteriorates the geological heterogeneity. During the development process, the following problems often appear, such as: prominent plane contradictions, plane injection water rushes along the high permeability zone to form waterways; prominent interlayer contradictions, unev...

AI Technical Summary

Problems solved by technology

In recent years, although tertiary oil recovery measures such as polymer flooding have achieved better results, there are still problems such as high cost of oil displacement and difficulty in field implementation; ” in the reservoirs, there are still serious problems of channeling and accumulation in some wells, which affects the effect of polymer injection, and due to the limitations of the polymer itself, the effective viscosity loss in high-temperature and high-salinity formations is very large, often Can't achieve the expected purpose

ASP flooding technology has gradually been widely used in Daqing and other old oilfields. The use of surfactants to reduce interfacial tension greatly reduces capillary force, and oil and water achieve miscible flow, thus starting the low permeability reservoir. Residual oil, but ASP flooding technology and polymer flooding have similar problems: shear thinning, affected by reservoir conditions, and both polymer flooding and ASP flooding will pollute oil-bearing low-permeability layers, making subsequent water flooding unable to achieve best results

Flexible particles can form dynamic plugging in the deep part of the reservoir, but for fractures and ultra-high permeability layers caused by high-intensity water erosion near the well, high-strength plugging agents must be used for anti-channeling operations, otherwise the flexible diverting agent can improve recovery The effect of the rate cannot be brought into full play

[0007] To sum up, so far, in the water plugging and profile control technology of oil production, the profile control and the adjustment of the oil-water mobility ratio cannot be carried out simultaneously, and no prior art reports have solved this problem.

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